Stop signal inhibit control for paper cutting machines

ABSTRACT

A paper cutting machine control is provided for purposes of controlling the positioning of a movable back gauge relative to a guillotine type tool in dependence upon position command marks recorded on a record member. The back gauge is normally advanced toward the tool at a high speed and relative motion is imparted between the record member and the mark sensors proportional to the velocity of the back gauge. One of the mark sensors serves to sense a mark in advance of that by the second mark sensor and provides a low speed signal for application to a low speed control means to control movement of the back gauge at a low speed. The second mark sensor senses each mark subsequent to that by the low speed sensor, and serves to provide for each sensed mark a stop signal. Circuit mean serve to provide a manifestation, such as an electrical signal or the closure of relay contacts, representative that the back gauge is moving at the low speed. A stop control means serves to control the back gauge to a stopped condition in response to concurrent occurrence of the manifestation and the stop signal and thereby prevent the back gauge from being stopped in the event that a stop signal is provided while the back gauge is moving at a high speed.

Murray et a1.

[ STOP SIGNAL INHHBIT CONTROL FGR PAPER CUTTING MACHINES [75] Inventors: James E. Murray, University Heights; Richard G. Foley, Dayton, both of Ohio [73] Assignee: Harris-Intertype Corporation,

Cleveland, Ohio [22] Filed: Nov. 27, 1970 [21]- Appl. No.: 93,373

[52] US. Cl. .318/467, 318/600, 2l4/l.6 [51] Int. Cl. ..G05d 3/00 [58] Field of Search.-.....318/600, 467, 257, 142, 158; 214/1.6

[56] References Cited UNITED STATES PATENTS 3,193,745 7/1965 Brown ..318/630 3,192,808 7/1965 Fielder et al.... ....3lS/600 X 2,655,994 10/1953 Vandenberg ....318/l58 X 2,692,361 10/1954 Asbury et a1. ..318/142 2,933,626 4/1960 Giboney et al. ..318/6 X 3,048,751 8/1962 Taylor ....318/257 X 3,181,403 5/1965 Stems et a1. ....3l8/600 X 3,195,385 7/1965 Paterson..... ,...318/600X 3,419,800 12/1968 Levi et a1 ....318/600 X 3,445,640 5/1969 Harrison et a1 ..318/600 X 1 March 6, 1973 Primary Examiner-T. E. Lynch Attorney-Yount and Tarolli 5 7] ABSTRACT A paper cutting machine control is provided for purposes of controlling the positioning of a movable back gauge relative to a guillotine type tool in dependence upon position command marks recorded on a record member. The back gauge is normally advanced toward the tool at a high speed and relative motion is imparted between the record member and the mark sensors proportional to the velocity of the back gauge. One of the mark sensors serves to sense a mark in advance of that by the second mark sensor and provides a low speed signal for application to a low speed control means to control movement of the back gauge at a low speed. The second mark sensor senses each mark subsequent to that by the low speed sensor, and serves to provide for each sensed mark a stop signal. Circuit mean serve to provide a manifestation, such as an electrical signal or the closure of relay contacts, representative that the back gauge is moving at the low speed. A stop control means serves to control the back gauge to a stopped condition in response to concurrent occurrence of the manifestation and the stop signal and thereby prevent the back gauge from being stopped in the event that a stop signal is provided while the back gauge is moving at a high speed.

8 Claims, 4 Drawing Figures STOP SIGNAL INHIBIT CONTROL FOR PAPER CUTTING MACHINES This invention relates to the art of paper cutters and, more particularly, to an improved paper cutter control system having provisions for preventing a back gauge from being decelerated directly from a high speed to a stopped condition without first being decelerated to a low speed.

Paper cutting machines typically comprise a worktable upon which a back gauge is slideably movable for purposes of positioning a pile of material, such as paper, to be cut by a guillotine type cutting tool. The positioning of the back gauge, and, hence, the pile of material to be cut, is controlled pursuant to a cutting program typically recorded as magnetic or optical marks on a record member. The command marks are sequentially read first by a deceleration sensor head for purposes of decelerating the back gauge from a high speed to a low speed, and then by a stop head for stopping further movement of the back gauge so that a cutting operation may be performed. Once the cutting operation has been completed, the back gauge may be further advanced toward the cutting tool at the high speed so as to minimize the time required to advance material to the cutting position. The sensors may be stationary and the control record moved passed the sensors at a speed proportional to that of the back gauge, or, if it is desired, the control record may be stationary and the sensors be moved at a speed proportional to that of the back gauge.

The back gauge presents substantial inertia and, hence, when traveling at the high speed it is difficult to decelerate it to a stopped condition so as to precisely position material for a cutting operation. It is for this reason that the back gauge is first decelerated to the low speed from which it may be more easily decelerated to a stopped condition with the material precisely positioned for the cutting operation. If a command mark has, in effect, been missed by the deceleration sensor head, as through a circuit malfunction, the pile of material would advance at the high speed, rather than the low speed, to the cutting position. If the back gauge is decelerated directly to a stopped condition in response to the missed mark" being sensed by the top sensor, then the pile of material may be inaccurately positioned. If a cutting operation is performed the work product will be wasted and must be discarded. It would be preferable in the case of a missed mark that the stop sensor head be rendered ineffective so that the back gauge is not directly decelerated from the high speed to a stopped condition, since a missed cutting operation can be performed at a later time without wasting the material.

The present invention is directed toward an improved control system for paper cutting machines which serves to render a stop signal ineffective to stop the back gauge when the back gauge is not moving at the low speed. a

The present invention contemplates that a paper cutting machine be provided with a control mechanism for purposes of controlling the positioning of a movable back gauge relative to a cutting tool in dependence upon command marks recorded on a record member. A pair of mark sensors serve to sense the marks and relative motion is provided between the record member and the sensors proportional to the velocity of the back gauge. It is also contemplated that the control mechanism serves to normally control the back gauge for operation at a high speed, and that one of the mark sensors is positioned to sense a mark in advance of that by the second mark sensor for purposes of providing a low speed control signal for application to a low speed control circuit or the like to control the back gauge to move at a low speed. Further, it is contemplated that the second mark sensor sense each mark subsequent to that by the first mark sensor means and provide a stop signal.

In accordance with the present invention, circuit means serve to provide a manifestation, such as an electrical signal or the closure of a set of relay contacts or the conditioning of other switching means including solid state switching means, representative that the back gauge is moving at the low speed. A stop control serves to control the back gauge to a stopped condition only in response to concurrent occurrence of the manifestation and the stop signal. In this manner, the back gauge is prevented from being decelerated directly from the high speed to the stopped condition in response to a mark being sensed by the stop sensor.

In accordance with a more limited aspect of the present invention, the manifestation providing circuitry includes switching means, such as relay contacts or the like, having a normal first condition when the back gauge is moving at the high speed and a second condition for providing the manifestation when the back gauge is not moving at the high speed.

Still further in accordance with the present invention, control circuitry is provided for actuating the switching means to the second condition each time a low speed signal is provided and for a period corresponding with a predetermined travel distance of the back gauge, which preferably is slightly in excess of the distance between the two sensor heads.

The primary object of the present invention is to provide improved control of the positioning of a back gauge used in a cutting machine.

A further object of the present invention is to prevent a back gauge in a cutting machine from being directly decelerated from a high speed to a stopped condition as opposed to being first decelerated to a low speed and then decelerated to a stopped condition.

The foregoing and other objects and advantages of the invention will become more readily apparent from the following description of the preferred embodiment of the invention taken in conjunction with the accompanying drawings which are a part hereof and wherein:

FIG. I is a side view of a paper cutter machine to which the present invention may be applied;

FIG. 2 is a front elevational view showing a magnetic tape having marks magnetically recorded thereon together with magnetic sensors for controlling the position of a back gauge relative to a cutting tool;

FIG. 3 is an enlarged perspective view of a portion of the magnetic tape and the sensors shown in FIG. 2; and,

FIG. 4 is a combined schematic-block diagram illustration of a control circuit employing the present inven- During the cutting operation, material 12 is held in place by a clamp 16. A back gauge 18 is slideably movable along table and serves to position the material 12 beneath the knife. Back gauge 18 is slideably moved along the surface of the table 10 by means of a lead screw 20 rotatably supported beneath the table. Lead screw 20 may be turned to adjust the position of back gauge 18 by means of a hand wheel 22. During normal operation, however, it is contemplated that lead screw 20 be turned by means of a dual speed electric motor M for positioning the back gauge in dependence upon commands from a position controller 26.

The position controller 26, as shown in FIGS. 2 and 3, includes a record member 24 taking the form of a magnetic tape formed into a continuous belt divided longitudinally throughout its length by a plurality of evenly spaced sprocket holes 27. The record member 24 is reeved over sprocket wheels 28 and 30 so that the sprocket holes 27 mesh with teeth provided on the two sprocket wheels. Sprocket wheel 30 is driven by lead screw 20, as through a coupling chain 32, so that record member 24 is driven at a speed dependent on that of the back gauge 18. Whereas record member 24 is illustrated as being driven at a speed having a 1:1 ratio with back gauge 18, it is contemplated that speed reduction means may be provided so that the speed relationship, while proportional, need not be at a 1:1 ratio.

In accordance with a programmed cutting operation, marks are magnetically recorded on record member 24. For example, marks 40 and 42 are recorded and spaced apart in aligned fashion in a single track so as to be sequentially sensed first by a deceleration sensor head 44 and then by a stop sensor head 46 which are spaced apart in aligned relationship to sense the marks in a particular track. Sensing head 44 is designated the deceleration sensing head since upon sensing a mark it provides a low speed control signal which through suitable circuitry, to be described hereinafter with reference to FIG. 4, serves to control motor M to decelerate from a high speed to a low speed. The tape then moves at a slow speed for a distance dependent on the spacing between heads 44 and 46, and then the mark is sensed by head 46 which provides a stop signal.

This signal, as will be described in greater detail hereinafter, causes the motor to be decelerated from the low speed condition to a stopped condition, at which time a cutting operation is performed.

Whenever a mark, such as mark 42, is sensed by a deceleration head 44 it is desired that the control record, and, hence, the back gauge, be controlled to move at a low speed for a distance at least slightly greater than the distance between deceleration head 44 and the stop head 46. This is necessary because motor M is normally operated to run at the high speed and, hence, if mark 40 is located behind mark 42 by a distance less than the distance between sensors 44 and 46 the motor, after having been stopped in response to head 46 sensing mark 42, will then be operated at a high speed until mark 40 is sensed by sensor 46. Because of the inertia effects of stopping back gauge 18 at the high speed it is desirable that mark 40 be sensed by stop sensor head 46 while traveling at the low speed. For this reason means are provided to insure that record member 24, and hence back gauge 18, travel a distance slightly greater than the distance between sensor heads 44 and 46 for each mark sensed by deceleration sensor head 44. This may be accomplished in various fashions. For example, since sprocket holes 27 are uniformly spaced the number of sprocket holes passing a particular point may be related to the distance between sensor heads 44 and 46. The sprocket holes may be counted, for example, with the use of a conventional lamp-photo sensor arrangement, such as lamp 50, positioned to transmit a beam of light through an apertured mask 52 so as to pass through each sprocket hole 27 and be received by a photosensor 54. The photosensor may be any conventional photosensor, such as a phototransistor or photodiode, which serves to provide an output signal pulse for each sprocket hole which passes through the lamp-photo sensor arrangement. The output signal pulses from photosensor 54, as will be explained in greater detail hereinafter, are applied to a counter which together with accompanying circuitry serves to insure that control record member 24 and, hence, back gauge 18 move at the low speed for a predetermined distance equal to a distance slightly greater than the spacing between sensor heads 44 and 46 each time a magnetic mark is sensed by deceleration sensor head 44.

The deceleration sensor head 44, stop sensor head 46 and the photosensor 54 provide output signals which are processed by the control circuit CC, shown in FIG. 4, for purposes of controlling motor M in accordance with the program of magnetic marks recorded on record member 24. Thus, each time deceleration sensor 44 senses a magnetic mark, such as mark a, on record member 24 a pulse is generated and applied to a conventional operational amplifier 60 whose output signal pulse is, in turn, shaped to a suitable form by means of a conventional pulse shaping circuit 62. For each magnetic mark sensed by sensor head 44 pulse shaping circuit 62 applies a pulse to the reset input of a pulse counter circuit 64. Pulse counter circuit 64 may take various forms but preferably serves to provide an output signal only after a predetermined number of pulses from photosensor 54 have been counted subsequent to the receipt, at its reset input, of a pulse from pulse shaping circuit 62. For example, it may be assumed that five pulses from photosensor 54 are indicative that a mark has traveled from deceleration head 44 for a distance just exceeding that to stop sensor head 46. Once this distance has been traversed then it is permissible for the motor M to operate at the high speed. Consequently, counter 64 is preset to provide a ground or binary 0" output signal upon receipt of a pulse from pulse shaping circuit 62 indicative that a mark has been sensed by deceleration sensor head 44. Thereafter, the counter must count five pulses from photosensor 54, without being reset, and will then provide a positive, or binary 1, signal on its output circuit. After a mark, such as mark a, has been sensed by deceleration sensor head 44 and before five pulses have been counted from photosensor 54, the output circuit of counter 64 applies a ground, or binary 0", signal to a conventional inverter amplifier 66 so that its output circuit, in turn, carries a binary 1" signal. The binary l output signal from amplifier 66 serves to energize a motor slow control relay coil SL which, as will be described in greater detail below, serves to command the motor to decelerate from its normal high speed to its low speed and also to permit a subsequent stop signal provided by sensor head 46 to cause further deceleration of the motor to a stopped condition.

Each time the stop sensor head 46 sensed a mark, such as mark a, a pulse is generated and applied to a conventional operational amplifier 70 whose output signal pulse is, in turn, shaped to a suitable form by means of a conventional pulse shaper circuit 72. The signal pulse provided by pulse shaper circuit 72 is used to energize a motor stop control relay coil SA for purposes of controlling motor M to decelerate to a stopped condition. However, relay coil SA can only be energized when normally open relay contacts SL-ll are closed, as upon energization of relay coil SL.

Upon a momentary closure of a start switch 80 a circuit is completed between a 8+ voltage supply source and ground through normally closed stop relay contacts SA-l and both a forward control relay coil F and a parallelly connected holding relay coil A. Both of these relay coils become energized and coil A serves to close associated normally open relay contacts A-ll connected in shunt with switch 80 to provide a holding circuit. This maintains coils A and F energized once switch 80 is opened. These two coils, of course, will become deenergized once relay contacts SA-l open.

When relay coil F is energized its normally open contactsF-l are closed so that a path is completed through contacts F-l, normally closed relay contacts SA-3 and SL-3 to maintain a motor fast clutch coil 90 energized. So long as the fast clutch coil 90 is energized the motor M, in a conventional fashion, will serve to drive lead screw and, hence, back gauge 18 at the high speed. In addition, when forward relay coil F is energized its normally closed contacts F4 are open so as to deenergize brake coil 92.

Once deceleration sensor head 44 has sensed a mark, such as mark a, counter 64 will be reset so that slow relay coil SL is energized. Consequently, its normally closed relay contacts SL-3 will open to deenergize motor fast clutch coil 90. The slow relay coils normally open contacts SL-2 will become closed to complete a path from the B+ voltage supply source through relay contacts F-l and SA-3 to energize a motor slow clutch coil 94, which serves to decelerate motor M from its high speed to the low speed. In addition, normally open contacts SL-l become closed to permit energization of the stop relay coil SA until counter 64 counts out.

In the example given above, relay coil SL is energized so long as counter 64 has not counted out. Thus, each time sensor head 44 provides an output pulse, counter 64 is reset and commences to count five pulses from photosensor 54 during which period relay coil SL is energized. It is during this period that relay coil SA may be energized in response to sensor head 46 sensing a magnetic mark on record member 24. When stop relay coil SA is energized its normally open contacts SA2 close to energize brake coil 92 and thereby decelerate motor M from the low speed to its stopped condition. in addition, when relay coil SA is energized its normally closed contacts SA-3 are open to prevent motor slow clutch coil 94 as well as motor fast clutch coil 90 from being energized. Also, relay contacts SA-l open to deenergize both the forward relay coil F as well as the holding circuit relay coil A. It is during the stopped condition of motor M that the cutting operation may be performed.

It is contemplated that when the cutting operation is completed suitable means will momentarily close switch dill so that brake coil 92 will be deenergized to permit continued operation of motor M. If counter 64 has not completed its counting function then, upon closure of switch d0, motor M will be operated to drive back gauge 18 at its slow speed since the slow relay coil SL will be energized. Once counter 64 has counted out, the slow relay coil SL will be deenergized. This will cause clutch coil 94 to be deenergized and clutch coil to be energized so that the motor will drive back gauge 18 at the fast speed. If for some reason, as through a circuit malfunction, a mark is now missed by sensor head 44 and is subsequently sensed by sensor head 46 the stop relay coil SA will not become energized, as the slow relay contacts SL-ll are open. The circuitry, therefore, will cause energization of brake coil 92 only on the concurrent occurrence of a stop signal and a manifestation or indication, as by closure of contacts SL-ll, that the back gauge is traveling at the slow speed.

The invention has been described with reference to a preferred embodiment, however, it is to be appreciated that the invention is not limited to same as various modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.

What is claimed is:

l. in a material cutting machine for controlling the positioning of a movable back gauge relative to a cutting tool and comprising:

a record member having position command marks recorded thereon;

first and second mark sensing means;

means for imparting relative motion between said record member and said sensing means proportional to the velocity of said back gauge;

said first mark sensing means being positioned to sense a said mark in advance of that by said second sensing means as said back gauge moves toward said cutting tool, said first mark sensing means providing a low speed signal for each mark sensed thereby and said second mark sensing means providing a stop signal for each mark sensed thereby;

high speed control means for normally controlling said back gauge for operation at a high speed toward said cutting tool;

low speed control means including means responsive to a said low speed signal for decelerating said back gauge from said high speed to a low speed;

stop control means including means responsive to a said stop signal applied thereto for decelerating said back gauge to a stopped condition; and

means for ensuring that said back gauge is first decelerated to said low speed from said high speed before being decelerated to a said stopped condition in response to a said stop signal and including circuit interrupter means interposed between said second mark sensor means and said stop signal responsive means and controlled by said low speed control means to apply a said stop signal to said stop signal responsive means only when said back gauge is moving at said low speed.

2. In a material cutting machine control as set forth in claim 1, wherein said interrupter means includes switching means having a normal first condition when said back gauge is moving at said high speed and a second condition when said back gauge is not moving at said high speed.

3. In a material cutting machine control as set forth in claim 2 wherein said switching means includes relay contacts.

4. In a material cutting machine control as set forth in claim 1 wherein said high speed control means includes first switching means normally in a first condition during which said back gauge is controlled for movement at a high speed and actuatable to a second non-controlling condition; and, switch control means for, in response to each said low speed signal, actuating said switching means to a second condition for a period dependent upon a predetermined travel distance of said back gauge so that during said predetermined travel distance said back gauge is prevented from moving at said high velocity.

5. In a material cutting machine control as set forth in claim 4 wherein said interrupter means includes second switching means having a normal first condition when said first switching means is in its first condition and a second condition when said first switching means is in its second condition.

6. In a material cutting machine control as set forth in claim 5 wherein said switch control means includes resettable counter means for counting a predetermined number of count pulses after receipt of a said low speed signal and then controlling said first and second switching means to their respective first conditions; and,

means for providing said predetermined count pulses when said back gauge travels said predetermined travel distance.

7. In a material cutting machine control as set forth in claim 1 wherein said record member is a magnetic record member and said marks are magnetic signal producing marks recorded thereon, each said sensing means exhibiting the characteristic of developing a signal pulse in response to relative movement between a said mark and the respective said sensing means.

8. In a material cutting machine control as set forth in claim 1 wherein said relative movement imparting means includes means for moving said record member, while said sensing means are stationary, at a speed proportional to that of said back gauge.

t: t a: i 

1. In a material cutting machine for controlling the positioning of a movable back gauge relative to a cutting tool and comprising: a record member having position command marks recorded thereon; first and second mark sensing means; means for imparting relative motion between said record member and said sensing means proportional to the velocity of said back gauge; said first mark sensing means being positioned to sense a said mark in advance of that by said second sensing means as said back gauge moves toward said cutting tool, said first mark sensing means providing a low speed signal for each mark sensed thereby and said second mark sensing means providing a stop signal for each mark sensed thereby; high speed control means for normally controlling said back gauge for operation at a high speed toward said cutting tool; low speed control means including means responsive to a said low speed signal for decelerating said back gauge from said high speed to a low speed; stop control means including means responsive to a said stop signal applied thereto for decelerating said back gauge to a stopped condition; and means for ensuring that said back gauge is first decelerated to said low speed from said high speed before being decelerated to a said stopped condition in response to a said stop signal and including circuit interrupter means interposed between said second mark sensor means and said stop signal responsive means and controlled by said low speed control means to apply a said stop signal to said stop signal responsive means only when said back gauge is moving at said low speed.
 1. In a material cutting machine for controlling the positioning of a movable back gauge relative to a cutting tool and comprising: a record member having position command marks recorded thereon; first and second mark sensing means; means for imparting relative motion between said record member and said sensing means proportional to the velocity of said back gauge; said first mark sensing means being positioned to sense a said mark in advance of that by said second sensing means as said back gauge moves toward said cutting tool, said first mark sensing means providing a low speed signal for each mark sensed thereby and said second mark sensing means providing a stop signal for each mark sensed thereby; high speed control means for normally controlling said back gauge for operation at a high speed toward said cutting tool; low speed control means including means responsive to a said low speed signal for decelerating said back gauge from said high speed to a low speed; stop control means including means responsive to a said stop signal applied thereto for decelerating said back gauge to a stopped condition; and means for ensuring that said back gauge is first decelerated to said low speed from said high speed before being decelerated to a said stopped condition in response to a said stop signal and including circuit interrupter means interposed between said second mark sensor means and said stop signal responsive means and controlled by said low speed control means to apply a said stop signal to said stop signal responsive means only when said back gauge is moving at said low speed.
 2. In a material cutting machine control as set forth in claim 1, wherein said interrupter means includes switching means having a normal first condition when said back gauge is moving at said high speed and a second condition when said back gauge is not moving at said high speed.
 3. In a material cutting machine control as set forth in claim 2 wherein said switching means includes relay contacts.
 4. In a material cutting machine control as set forth in claim 1 wherein said high speed control means includes first switching means normally in a first condition during which said back gauge is controlled for movement at a high speed and actuatable to a second non-controlling condition; and, switch control means for, in response to each said low speed signal, actuating said switching means to a second condition for a period dependent upon a predetermined travel distance of said back gauge so that during said predetermined travel distance said back gauge is prevented from moving at said high velocity.
 5. In a material cutting machine control as set forth in claim 4 wherein said interrupter means includes second switching means having a normal first condition when said first switching means is in its first condition and a second condition when said first switching means is in its second condition.
 6. In a material cutting machine control as set forth in claim 5 wherein said switch control means includes resettable counter means for counting a predetermined number of count pulses after receipt of a said low speed signal and then controlling said first and second switching means to their respective first conditions; and, means for providing said predEtermined count pulses when said back gauge travels said predetermined travel distance.
 7. In a material cutting machine control as set forth in claim 1 wherein said record member is a magnetic record member and said marks are magnetic signal producing marks recorded thereon, each said sensing means exhibiting the characteristic of developing a signal pulse in response to relative movement between a said mark and the respective said sensing means. 